I'm completely ignorant when it comes to carbs, so that whole jetting talk is over my head at the moment. Besides the idle mixture screw are there any other adjusting screws on it to tune it, or is it just jets? It looks like there are 3 or 4 other adjustable screws on it but all the diagrams i've pulled up don't say what they are.

On another note, it does something that i have no clue if its normal or not. My fuel pump is wired to a switch i can turn off and on at will. If i turn the fuel pump off, the truck will continue to idle for about a minute or so before it eats up all the gas inside the carb and then dies. Is that normal on a carb? Engine turns off like it should when you turn the key off. Haven't checked to see how long it will run like that now that i have the return line hooked up.